2000 Dodge Durango After the veh warms up, has trouble shif

My vehicle was leaking alot of transmission fluid (because repair shop loosened the bolts on the pan. Unknown until recently). Put stop leak in along with more transmission fluid. Took vehicle to another shop was given an outrageous price to repair leak. When that shop put the pan back on fixed the leak problem, but now when the veh has warmed up (about 20 minutes of driving), having trouble shifting into the 3rd. Then after about 5 minutes have trouble shifting out of 1st.